Socket for an electrical lamp



Aug. 14, 1962 R. A. ECK El'AL 3,049,599

SOCKET FOR AN ELECTRICAL LAMP Filed Oct. 20, 1959 2 Sheets-Sheet 1 FIG. I

INVENTORS. ROBERT A. ECK NATHANIEL SILVER R. A. ECK EI'AL 3,049,599

SOCKET FOR AN ELECTRICAL LAMP Aug. 14, 1962 Filed Oct. 20, 1959 2 Sheets-Sheet 2 FIG. 5

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ROBERT A. ECK NATHANIEL SILVER Eflnlu 8- AGENT.

United States Patent 3,049,599 SOCKET FOR AN ELECTRICAL LAM? Robert A. Eek, Port Chester, N.Y., and Nathaniel Silver,

Stamford, (Ionm, assignors to Nathaniel Silver, Stamford, Conn.

Filed Get. 20, 1959, Ser. No. 847,587 9 Claims. (Cl. 200-5117) This invention is related to sockets for electrical lamps and has particular reference to a socket which is adapted to operate in conjunction with a multi-filament incandescent lamp or the like.

The requirement for achieving varying degrees of light output from an incandescent lamp is well known in the art. The light developed by a single filament incandescent lamp readily can be varied by adjusting the current flowing through the filament by either using a series connected rheostat or a variable voltage transformer. The first method is rather expensive and inefficient as far as power consumption is concerned, while the latter method requires relatively expensive and bulky equipment. Both methods, still further, materially affect the filament life.

In view of the shortcomings with respect to single filament bulbs, multi-filarnent bulbs have been developed, primarily lamps which are equipped with two independent and suitably rated filaments whereby such filaments become excited either individually or in combination to obtain a total of three degrees of luminosity from the single device. While the three degrees of luminosity may sufi-ice in some instances, there always has been recognized the need for a greater degree of flexibility to reconcile the light output with individual surroundings, to adjust the lighting to personal preferences, or to provide special situations and effects as are readily apparent to those skilled in the art.

Although multi-filarnent bulbs using more than two incandescent filaments have been known in the art for some time, investigations have shown that most of the sockets available for such lamps are afiiicted with many and inherent shortcomings. By way of example, almost all of the sockets can be turned only in one direction, thus requiring the user to proceed through a predetermined cycle of varying luminosity before being able to adjust the light output to the desired value. Moreover, most of the sockets are relatively expensive, bulky, and subject to wear by breaking of springs, detents, etc.

In conjunction with the development of a new, improved and rugged multi-filament incandescent lamp, it was desirable therefore to design and develop simultaneously an improved socket which would overcome many of the failings of the prior art devices.

One of the objects of this invention therefore is the provision of a new and improved socket for multi-filament incandescent lamps which overcomes one or more of the disadvantages and limitations of prior art devices.

Another object of this invention is the provision of a lamp socket which retains the lamp and wherein the luminosity of the lamp may be adjusted by means of a bidirectionally rotatable control knob.

Another object of this invention is the provision of a small and compact socket and switch combination which can be manufactured in an inexpensive manner and which may be used interchangeably for operation in conjunction with a single filament, double filament, or multi-filament incandescent lamp.

Another object of this invention is the provision of a socket and switch mechanism which is selectively adjustable for a large number of electrical connections and permutations.

Another object of this invention is the provision of a new and novel switching mechanism, which among other advantages, is selectively rotatable in clockwise or counterclockwise direction through any angle from zero to 360 degrees.

A further object of this invention is the provision of a lamp socket employing selectively movable tumbler assemblies which are adapted to establish electrical contact between the terminals of a lamp or similar electrical apparatus and a stationary contact plate.

Another and still further object of this invention is the provision of a socket using tumbler assemblies which are biased in two directions so as to adjust themselves for varying degrees of wear of the associated mechanism and apparatus.

Further and still other objects of this invention will be apparent by reference to the following description taken in conjunction with the accompanying drawings in which:

FIGURE 1 is an exploded elevational view of the socket and lamp assembly including the novel switching mechanism;

FIGURE 2 is a top plan view of the switching mechanism;

FIGURE 3 is an enlarged elevational view, partly in section, of the switching mechanism;

FlGURE 4 is an exploded view of the socket with the novel electrical circuit switching mechanism;

FIGURE 5 is a sectional view along lines 5-5 in FIGURE 4 showing more clearly the construction of the tumbler assembly;

FlGURE 6 is an elevational view, partly in section, showing a variation of the contact arrangement, and

FlGURE 7 is a further alternate design showing the use of the novel switching mechanism remote from the lamp socket.

Referring now to the figures and FIGURE 1 in particular, the entire assembly is shown in exploded and partially sectioned view. Numeral lil identifies a light bulb provided with a transparent or translucent glass envelope 11 enclosing therein four incandescent filaments, numetals 12, 13, 14, and 15. The filaments are supported in the lamp envelope in the usual manner which is well known in the art. The lamp at its lower end is equipped with a standard metal screw shell 16 and the filaments are terminated at the bottom of the shell in suitable electrical contact points 17. Numeral 2t) identifies a conventional metal shell which mates at its lower end with a metal cap 21, both being well known in the art. Additionally, the entire assembly includes an insulated tubular portion 22 made of cardboard, wax paper or other suitable insulating material.

The new switching mechanism and lamp retaining means 23 is enclosed between cap 21 and shell 29, and is surrounded by insulated tubing 22. As its main components the lamp retaining and switching mechanism 23 hereafter referred to as socket includes a threaded metal shell 24 into which the lamp screw shell 16 is threaded, a frame member 25, made of insulating material such as Lucite, Plexiglas, or other suitable material, and a control knob 26 which is turned for adjusting the varying degrees of luminosity available from the lamp.

Since the lamp 10 is provided with four distinct filaments, it will be apparent that aside from an OFF position there must be available twelve distinct positions for obtaining all of the possible combinations of luminosity.

The novel switching mechanism will be better understood by reference to FIGURES 3 and 4 which show a rotatable drum 31 being provided about its circumference with four suitably arranged and shaped protrusions 32, each of which thus forms a cam surface. Drum 31 preferably is made of electrically non-conductive material and the cam surfaces may form a part thereof by suitable molding techniques. The drum with its cam surfaces is retained in a bifurcated extension of frame member 33 using a set screw 34 and a control knob 26 which reach through the frame member and engage the drum. When the drum is held in place, control knob 26 may be rotated to cause rotation of drum 31 and associated cam surfaces 32. Within the frame member there is disposed a switch assembly 36 which comprises four selectively movable tumbler mechanisms. The assembly includes a stationary contact plate 61 and selectively movable tumbler mechanisms movable relative to one another and the plate. As the cam rotates, the tumbler pins 69 are selectively urged in axial motion and the corresponding associated upper bushings 66 are raised and lowered in longitudinal direction through a corresponding aperture in the frame. Thus, the pins and bushings are in concomitant motion, each bushing 66 contacting one of the filament terminations when the corresponding pin is raised. This operation occurs in such a sequence as to account for the twelve possible permutations as well as the OFF position of the switch assembly for each revolution of the control knob 26. It will be noted however that when bushing 66 of the tumbler mechanism assumes its lowermost position, it is withdrawn below the top surface of the frame member as shown clearly by numeral 46 in FIGURE 3. The frame member, if desired, may be made of a plurality of parts which are bonded or fused together when the switch mechanism has been inserted therein. Alternately, the frame member may be molded around the switch mechanism by well known molding techniques.

The lamp is held in the socket assembly by means of threaded screw shell 24 which is bent over at the bottom to provide a flanged surface for attachment to frame member 33. Screws 42 and 43 fasten the shell 2'4 to the frame. Screw 43 being in electrical contact with the metal shell 24, in turn screws into metal strip 44 by means of which electrical connection is established through the shell to lamp base 16 using screw 45 in the well known manner.

The construction of the tumbler assemblies will more clearly be apparent by reference to FIGURES 2, 4, and 5. A stationary contact plate 61, preferably made of brass, is provided with an extension 62 which at its far end is bent in a downward direction and receives a contact screw 63. In this manner, electrical contact is made to stationary contact plate 61. Plate 61 in turn is equipped with a plurality of tubular projections 65, see FIGURE 5, there being one projection for each tumbler assembly. Within each projection there is disposed for slidable motion a bushing 66 and a helical compression spring 67, the latter urging bushing 66 toward downward movement. Bushing 66 is provided also with an internal cavity which houses a further spring 68 and a sliding pin 69 biased by the spring relative to bushing 66. The lower end of pin 69 is engaged by one of the respective cam surfaces 32 and when the cam urges pin 69 into upward motion, this motion is transmitted to bushing 66 via biasing spring 68 so that bushing 66 is urged into concomitant motion and establishes contact with the respective filament termination 17. As soon as the cam surface permits downward motion of pin 69, spring 67 urges bushing 66 away from contact with the filament terminal. Since bushing 66, springs 67 and 68, and pin 69 are made of electrically conductive materials and in sliding contact with one another, there is electrical connection between terminal screw 63 and the respective filament terminal to be engaged. Moreover, it may be noted that each tumbler assembly is, so to speak, floating to compensate for mechanical irregularities or wear on the cam surface or unevenness or wear and manufacturing inaccuracies of the filament terminal. Also, inaccuracies inherent in the manufactured parts do not affect adversely the operation of the electrical circuit make andbreak arrangement.

It may be noted further that all of the tumbler assemblies disposed in contact plate 61 are at the same potential so that there is no problem of electrical insulation or arcing between the selectively movable tumbler assemblies. As the desired tumbler is raised, electrical circuit connection is established from screw 63, via extension 62, plate 61, bushing 66, and terminal 17 to one of the filaments, and from there via shell 16, mating shell 24, screw '43, strip 44 to screw 45.

Prolonged testing furthermore has shown that the contact surfaces between pin 69, bushing 66, and contact plate 61 are adequate to carry the necessary current so that there exists substantially no arcing. Also we have found no undue arcing between bushing '66 and the contact terminals 17 of the lamp. As an important safety feature, it will be noted that in the OFF position all pins 66 are withdrawn into the plastic frame as denoted by recess 40 in FIGURE 3 so that the socket presents a dead top surface.

A variation of the foregoing arrangement is visible in FIGURE 6 wherein an intermediate insulated element having a fixed, double headed contact rivet 81, made of electrically conductive material, is interposed between bushing 66 and a contact terminal 82. The purpose of this arrangement is to eliminate repetitive mechanical contact engagement between bushing =66 and contact terminal 82 which may be soft solder. By virtue of this arrangement after having once established contact between stationary member 80, rivet 81 and contact point 82, further circuits are made and broken only between bushing 66 and rivet 81.

A further variation of the foregoing assembly is shown in FIGURE 7 wherein the switching mechanism is housed in a separate enclosure and is mounted remote from the lamp and socket. As shown in FIGURE 7, lamp 91 is held in a socket 92 but the switching mechanism 90 is remote from the socket. Again, a plurality of tumbler assemblies can selectively be raised and lowered by operating a control knob 93. The operation of the drum, cam assemblies, floating plunger mechanisms, etc., is identical with the corresponding parts described hereinabove.

A still further variation which readily will be apparent to those skilled in the art comprises the use of a resiliently biased contact rivet 81 mounted for axial motion in element 80, see FIGURE 6. In its preferred embodiment, rivet 81 is provided with a longer shank and is normally biased in the upward direction. In this manner, the rivet too can adjust itself and compensate for irregular contours of contact 82? or the curvature of the lamp socket.

In general, it will be observed that the switch and socket assembly described in the foregoing specification is characterized by a minimum number of parts, by extreme simplicity and moreover, exhibits cooperation of the individual parts in such a manner as to provide long and trouble free operation of all items involved. Still further, the number of permutations available is extremely large and provided by very inexpensive and simple assemblies. The same switching principle, using more or fewer tumbler assemblies, may be used for many other electrical circuits aside from an incandescent lamp described hereinabove for illustrative purposes.

By suitably dimensioning and spacing of the tumbler assemblies, it has been possible to design a single socket which is useable in conjunction with the conventional single filament bulb, the conventional two-filament bulb, as well as with the lamp incorporating four filaments disclosed hereinabove. The instant lamp socket therefore, truly may be termed a universal socket.

While there have been described and illustrated certain specific embodiments of the present invention, it will be apparent to those skilled in the art that various other changes and modifications may be made therein without deviating from the intent and spirit of the present invention which should be limited only by the scope of the appended claims. I

What is claimed is:

1. An electrical switching means comprising a stationary plate, and a tumbler assembly in electrical contact therewith which includes: a bushing slidably mounted in said plate; resilient biasing means between said plate and the bushing; a pin slidably extending out of the bushing; resilient biasing means between said pin and bushing, and means engaging said pin for raising and lowering it relative to the plate whereby the bushing is urged in concomitant motion relative to the plate.

2. An electrical switching means comprising: a stationary electrically conductive plate; an apertured projection extending from the plate; an electrically conductive bushing disposed for axial motion within said projection; resilient biasing means disposed between the outside of said bushing and the apertured projection; an internal cavity in said bushing; an electrically conductive pin disposed for axial motion in said cavity; resilient biasing means confined in said cavity and engaging one end of said pin; cam means engaging the other end of said pin to urge the bushing in concurring axial motion with the pin relative to the plate and the projection thereon, and said pin adapted to establish an electrical circuit between said pin, said bushing and plate.

3. An electrical switching means as set forth in claim 2 wherein said cam means are electrically non-conductive.

4. An electrical switching means comprising: a stationary electrically conductive plate; an electrically conductive, resiliently biased tumbler assembly disposed in said plate being adapted to be raised or lowered relative to the top and bottom surfaces of said plate; an electrically non-conductive apertured member covering the top surface of said plate; said tumbler assembly disposed to move within the aperture of said member; means engaging said tumbler assembly for causing its motion relative to the plate, and said tumbler assembly when raised to its uppermost position protruding from the top surface of the non-conductive member and when lowered to its lowermost position being Withdrawn below the top surface of said non-conductive member.

5. A socket for an electrical lamp or similar article comprising: a receptacle adapted to support the lamp; a stationary electrically conductive plate disposed in said receptacle; an electrically conductive, resiliently biased tumbler assembly mounted in said plate being adapted to be raised or lowered relative to the top and bottom surfaces of said plate and being adapted to establish electrical contact with the lamp when raised; an electrically non-conductive apertured member covering the top surface of said plate; said tumbler assembly disposed to move within the aperture of said member; cam means journalled in said receptacle and engaging the tumbler assembly for causing its motion relative to the plate, and

said tumbler assembly when raised to its uppermost position protruding from the top surface of the non-conductive member for engaging the lamp and when lowered to its lowermost position being Withdrawn below to the top surface of said non-conductive member to break electrical connection with t re lamp.

6. An electrical switching means comprising a stationary plate, and a tumbler assembly in electrical contact therewith which includes: a bushing slidably mounted in said plate; first resilient biasing means between said plate and the bushing for urging said bushing to move along a first direction; a pin slidably extending out of the bushing; second resilient biasing means between said pin and bushing for urging said pin to move in the same direction as the bushing being urged in response to said first resilient means, and means for engaging said pin to move said pin selectively in the first direction and in a second direction which is opposite to said first direction whereby the bushing and pin are urged in concomitant motion.

7. An electrical switching means comprising a stationary plate, and a tumbler assembly in electrical contact therewith which includes: a bushing mounted for sliding motion in said plate; first biasing means engaging said plate and the bushing for urging said bushing to move in a first direction along an axis which is disposed centrally with respect to the bushing and at substantially right angles to the plane of said plate; an axial cavity in said bushing; a pin disposed in said cavity and mounted for sliding motion with respect thereto; second biasing means between said pin and bushing for urging said pin to move in the same direction as the bushing being urged by said first biasing means, and means for engaging said pin to move said pin selectively in the first direction and in a direction opposite thereto whereby the bushing and pin are urged in concomitant motion.

8. An electrical switching means as set forth in claim 7 wherein said bushing and pin move along a common axis.

9. An electrical switching means as set forth in claim 7 wherein said first biasing means are disposed in said axial cavity.

References Cited in the file of this patent UNITED STATES PATENTS 488,222 Rockwell Dec. 20, 1892 513,951 McFarlane et al. Jan. 30, 1894 626,017 Carroll May 30, 1899 670,927 Campbell Apr. 2, 1901 2,398,007 Hunter Apr. 9, 1946 FOREIGN PATENTS 832,772 France July 4, 1938 

